This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This is a (Category A) NIA-ACDS/Baxter Healthcare-sponsored 20 month (76 wk) trial comparing two doses of IVIG (200 or 400 mg/kg, q 2wk x 36 infusions) with placebo (0.25% albumin) to decrease the progression of dementia due to mild-moderate Alzheimer's disease already on routine therapy (cholinesterase inhibitors or memantine). Primary endpoints are based on ADAS-Cog and ADAS-CGIC instruments. Secondary measures are other neuropsychiatric measures, resource utilization, safety and tolerability, plasma biomarkers, and changes in (noncontrast) MRI. There are optional sub-studies which would allow 10y banking of DNA, repeated LP for CSF biomarkers (at baseline, 9 mo, and 18 mo), and/or FDG-PET (at baseline and 9 mo).